title: In situ sequestration of hydrophobic organic contaminants in sediments under stagnant contact with activated carbon. 1. Column studies.
abstract: The effectiveness of activated carbon (AC) treatment to sequester hydrophobic organic contaminants in sediments under stagnant contact was comprehensively studied for the first time. Two years of column experiments were conducted to simulate field conditions with two study sediments contaminated with petroleum and polychlorinated biphenyls, respectively, and variations in AC-sediment contact times, initial AC mixing regimes and distribution, AC particle sizes, and pore-water flow. The benefit of AC treatment was gradually enhanced with time toward the end point of the treatment, where sorption equilibrium is established between sediment and AC. After two years of stagnant contact, the contaminant uptake in polyethylene passive samplers embedded in the columns was reduced by 95-99% for polycyclic aromatic hydrocarbons and 93-97% for polychlorinated biphenyls with 5 and 4 wt % AC dose, respectively, when AC was initially applied by mechanical mixing. These results verify that AC treatment can effectively control the availability of hydrophobic organic contaminants under stagnant conditions within a reasonable time frame following an initial distribution of AC into the sediment. The effectiveness of AC treatment was strongly dependent on AC particle size and AC distribution, while the effect of AC initial mixing regimes and pore-water flow was not pronounced.
authors.affiliation: Department of Civil and Environmental Engineering, Stanford University , Stanford, California 94305-4020, United States.
authors.forename: Yongju
authors.initials: Y
authors.lastname: Choi
authors.forename: Yeo-Myoung
authors.initials: YM
authors.lastname: Cho
authors.forename: Richard G
authors.initials: RG
authors.lastname: Luthy
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D010316:Particle Size; D010578:Petroleum / Q000032:analysis; D059392:Petroleum Pollution / Q000517:prevention & control; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry*; D020959:Polyethylene / Q000032:analysis
chemical_list: D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D002606:Charcoal; D020959:Polyethylene; D011078:Polychlorinated Biphenyls